Sony SS-7660 ULM66
A floor-standing 3-way speaker system with variable bass tuning and ULM magnetic circuit technology, built for high-fidelity audio performance.
Overview
The Sony SS-7660 ULM66 is a floor-type, 3-way speaker system featuring a unique bass reflex/closed variable enclosure design. It uses a 30 cm cone woofer, and horn-type tweeter, with a frequency response from 30 Hz to 20,000 Hz. Designed for high input tolerance, it handles up to 100W of pink noise and delivers 89 dB/W/m sound pressure. Notably, it was not imported to the US, making it rare outside Japan.
Specifications
| Model Rating Method | 3-way, 3-speaker, bass reflex / closed variable system, floor type |
| Unit For low band | 30 cm cone type |
| Unit For High Frequency | Horn Type |
| Playback frequency band | 30 Hz to 20000 Hz |
| Output sound pressure level | 89dB/W/m (New JIS) |
| Impedance | 6 Ω |
| Maximum allowable input | 100W (weighted pink noise) |
| Crossover frequency | 600 Hz, 3 kHz |
| External dimensions | Width 499 x Height 750 x Depth 421 mm |
| Weight | Approximately 40 kg |
Design
The SS-7660 uses Sony’s Ultra Linear Magnetic Path (ULM) technology, featuring a notched center pole with copper plating to reduce magnetic distortion. It includes a metal bobbin woofer and high-rigidity cone paper made with Sony’s proprietary paper manufacturing process. The crossover uses large air-core coils to minimize distortion, and the system includes level controls for mid and high frequencies. A bass controller switches between closed, bass reflex, and intermediate modes below 100 Hz. A bypass switch removes the LC network for direct driver operation. The enclosure is built from 24 mm lauan plywood with acoustically shaped edges to reduce interference, and includes a noise-suppressing dust cap.
Market
Originally priced at ¥68,000 per unit around 1972, the SS-7660 is now rare in the collector market. One pair was listed for $950, described as “RARE!!” and noted as never officially sold in North America.
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